Engine Series – Ford Pre Cross-Flow

Lotus engine Series: The Ford Pre Cross-flow

Lotus races down the Old Kent Road


The engine series are neither technical treatise or Haynes Manuals. This information is readily available in published form or on the net.

Rather our study concentrates on how and why Chapman and his colleagues’ sourced engines and their contribution to Lotus success and sales.

In his selection of major mechanical components Chapman added both performance to a sophisticated chassis and extraordinary added value.

Lotus were not a major engine manufacturer until quite late on .Despite this they used and adopted a range of mainstream engines to extraordinary effect .

Chapman and Lotus practice provides inspiration for all Industrial Designers /Specialists in their search for urgency and added value.

Our study focuses heavily on the fitment of these engines along with a visual representation. We debate the appeal to owners / racers and the beneficial publicity accredited to the manufacturers.

We believe that subscribers will be well able from this base line to research specific topics according to their needs.

Subscribers might like to see the directly relevant and integrated A&R pieces that complement and help structure this article:-

  • See articles listed in other Ford engines covered i.e. Cross-flow, Cosworth,DFV,Consul and Side valve
  • Henry Ford
  • Lotus Seven related and Form and Function
  • Other engines that powered Lotus in dedicated series

Figure 1editors sketch: relative scale

Figure 2.Cutaway from Karberry.105 E

Ford Anglia 105 E

Kaberry wrote: –

“The introduction of the Ford Anglia 105E in October, 1959 can be described as revolutionary in motoring history. The principle of the over-sqaure engine introduced with the Consul and Zephyr Six was developed further, the stroke bore ratio in this case being 0.6:1.

So successful has this proved that the Anglia 105E engine is the basis of the power unit used in the highly successful Lotus cars used in Formula Junior racing. This car also was the first Ford passenger vechicle to be fitted with a four-speed gearbox………..

The engine used in the Anglia is a four-cylinder ohv unit fitted with a high compression cylinder head as standard. this gives a compression ratio of 8.9:1 [8.7 :1 for the 1200 super Anglia].

The valves are mounted vertically in the cylinder head, the valves guides being cast in the cylinder head, to provide good charging of the cylinders, the inlet valve heads are slightly larger in diameter than those of the exhaust valves …….

The cast steel crankshaft is supported in three main bearings of the replaceable steel backed liner type .similar bearings are also used in the connecting –rod ends ………the camshaft is located on the rhs of the cylinder block and operates the valve rockers through tappets and pushrods. A skew gear cut on the forward end of the camshaft drives both the distributor and oil pump; an eccentric at the rear end of the camshaft operates the mechanical fuel pump ………

the oil pump is mounted externally and is incorporated in the head of the full flow oil filter element .

The water pump is bolted to the front face of the cylinder block and is driven in tandem with the generator by a V-belt from the crankshaft ……”

Pre-Crossflow[edit] from wiki and the net :-

This survey is brief and ideal for a purpose of introduction:-

“The original OHV three main bearing Kent engine appeared in the 1959 Anglia with a capacity of 996.70 cc developing 39 bhp (29 kW) at 5,000 rpm – unusually high for the time. With a 80.96 mm (3.19 in) bore and 48.41 mm (1.91 in) stroke, combined with independent (non-siamesed) four intake and four exhaust ports, it was a departure from traditional undersquare English engine design.

1297 cc Kent engine in an Anadol A1

The same engine, with its bore unchanged, but with longer 65.00 mm and 72.75 mm stroke and thus larger capacities were subsequently used in the Ford Consul Classic (1339 cc) and Consul Capri (1339 cc and 1498 cc), the Mk1 and early Mk2 Cortinas (58.20 mm stroke 1198 cc, 63.00 mm stroke five main bearing 1297 cc and the 1498 cc), and the early Corsairs.

In addition to its ‘over-square‘ cylinder dimensions, a further unusual feature of the Kent engine at its introduction was an externally mounted combined oil filter/pump unit designed to facilitate efficient low-cost production and easy maintenance.[1]

The engine is now referred to as the pre-crossflow Kent, in reverse-flow cylinder head configuration with both the inlet and exhaust being on the same side of the head.


The Pre-Crossflow Kent engine was also used by Lotus on Lotus Mk.VII.”

Cross flow types:-







Figure 1.editors sketch Ford pre cross flow, with cross section from Haynes publications.Lotus Seven installation

Pre-cross flow from Weale

“when Ford introduced their 105 E “Kent” range of engines in 1959, replacing both the 1172 cc side valve and the larger Consul ohv the design was immediately regonised as something of significance- a really modern, compact, short stroke engine with obvious development potential, built as simply as possible with the minimum of parts.

The original use of the 105E engine in a Seven was a private conversion by Caterham …………….

In common with most mass –produced machinery, the Ford ohv engine has a complex history ……………

In Cosworth modified form, as fitted to the Seven, the 1340cc 109E engine developed approximately 85 bhp…………….the 1500 cc version was introduced in 1962 …………..this unit was offered in the Seven with a single ,side draught Weber DCOE carburetter in place of the Ford downdraught type .It also formed the basis of both the optional 95bhp , 1500 Cosworth engine , and the 1558 cc Lotus Cortina unit

These early Kent engines employed conventional chambered eight port cylinder heads, both inlet and exhaust manifolds being on the near side of the unit [ see editors sketches] and flat-topped pistons ………”

Figure 3.Period advertisement for pre cross flow engine/Ford cars

Figure 4.Editors sketch pre cross flow and gearbox.Remote change mechanism included

Statistics from Kaberry Ford 105E

996 .6cc Engine 1200 &Super Anglia
Bore 80.96 ditto
Stroke 48.41 58.17
Capacity 996.6 cc 1,198 cc
Compression ratio 7.5 & 8.9:1
Brake horse power
HC engine 39@5,000rpm 9.1 :1 [48.5@4,800] 50@4,900
LC engine 37@5,000rpm 7.8:1 [46@4,800] 48@4,900
Carburetter Solex/Ford d-d Solex
1st 4.118 to 1 3.543 to 1
2nd 2.396 to 1 2.396 to 1
3rd 1.412 to 1 1.412 to 1
4th 1.000 to 1 1.000 to 1
Rear axle ratio 4.125 or 4.444 to 1 4.125 to 1
Kerb Weight 1,680lb
Saloon 1,634lb
Estate car 1,820lb

Pre crossflow performance comparisons

Statistics from Haynes Guide to Component Cars.

mph 105E engine 116E Ford 122E modified 95 bhp
0-30 4.4 2.8 2.6
0-40 7.4 5 4.7
0-50 10.2 7.2 6.5
0-60 13.5 9.7 9.2
0-70 18.2 13 11.7
0-80 18.5 14.9
0-90 20.1
1st 24 26 34
2nd 34 40 50
3rd 64 70 86
4th 92 108 120
fuel cons’ 35mpg 30mpg 27mpg
hard 28mpg 25mpg 23mpg

Learning Opportunities

Our learning /educational opportunities are intended to be challenging thought provoking and requiring additional research and/or analysis.

These opportunities are particularly designed for a museum/education centre location where visitors would be able to enjoy access to all the structured resources available in conjunction with any concurrent exhibition.

In this instance we suggest the following might be appropriate:-

  • Why did the ford side vale remain so long in production?
  • What were ford’s main commercial considerations when designing a new engine series? [i.e. pre-cross flow]
  • How did ford diversify range to maximise production, sales and economy of scale?
  • What modifications did Cosworth make to base engine [ i.e. pre-cross flow]?
  • Why was unit particularly suitable for tuning? And use in Lotus Seven?
  • Examine performance figures for various Seven engines, how does pre-cross flow compare?

Figure 5. Editors sketch either side of engine


Cosworth modified engines are very significant aspect of Lotus commercial and competition success. For this reason, they are subject of a dedicated article.

The editors sketch is reminder of their importance particularly identified with the pre cross flow Lotus Seven’s………..to the extent they are considered the holy grail particularly the 109E version.

Exhibitions, Education and Economics

In the museum context the editors believe that commercial considerations are both necessary and complementary with its educational objectives.

For these reasons our suggested outline Business Plan includes provision for promoting products and services which share Chapman’s ideals of mechanical efficiency and sustainability. In addition we propose merchandising that explain and interprets the social and cultural context of Chapman’s designs in period. It’s suggested there will be catalogue for on line purchasing.

In this instance we suggest the following might be appropriate:-

  • Lotus races down the Old Kent Road
  • Kent over square: Congruous with Lotus
  • Kent over square: squarely bang, exactly right for Lotus
  • Kent over square: precisely and unswervingly correct for Lotus
  • Kent over square: More than
  • Kent over square: Overhead, over square
  • Lotus and Kent: Over and above
  • Lotus and Kent: no over reaction

Figure 6. Editors sketch of Cosworth modified Ford engine.Installation Lotus Seven


The Ford pre-cross flow “Kent” engine powered the Lotus

It therefore powered racing and road cars.

It was a superb piece of industrial design; functional and utilitarian .Although not without faults. Some of these might be due to subcontracting or Ford’s economy measures.

It was successful in racing gaining publicity and inspired modification, tuning and a generation chassis designers.

The engine was attractive to owners and generated sales. Exports were possible because of the international spares’ availability.

These mass-produced engines were generally robust, inexpensive, widely available and spawned aftermarket components industry. Furthermore, they invited experimentation, notably Cosworth and Holbay helped facilitate competition and design diversification. Thus, assisting and elevating British motor racing: design, engineering, manufacture and of course drivers.

The engine has continuing legacy and relevance and being such a significant piece of industrial design is fully worthy of analysis and appreciation.

Added value is an extremely important of Industrial Design, Chapman exploited to maximum effect and its principles are significant for a young entrepreneur with low capital wishing to enter the market.


The 100 most beautiful cars in pictures | Autocar


Lotus Seven.Weale.Osprey.1991.


Ford Anglia 105E.Kaberry.Pearson.1967.

Guide to Component Cars .Haynes. Haynes.c1966

Please see dedicated bibliographies listed with Lotus engine Series and Seven

Please note the editors of the A&R attempt to give the broadest spectrum of references but not all are available for consultation in an article. However by noting their existence it may assist students in their research.

*Items in italics non A&R library books.